1. Field of the Invention
The present invention relates to electrical relays and more particularly to electrical relays including one or more conducting loops concentric with a relay coil to cause the relay to concurrently serve as a current transformer.
2. Background and Related Art
In a common direct current (DC) operated relay, a direct current flowing through a relay coil magnetizes an iron (or other ferromagnetic) yoke assembly that causes the state of the switch to change. When the coil current is removed, a mechanical spring returns the switch to its original position. The relay on a car's starter motor is one example of such a relay. Other examples are found in many automotive and household applications.
Latching relays change state when their coil current is pulsed briefly, after which the switch remains in the new state. The coil is energized only while the relay changes state. This latching action is important when it is desirable to eliminate the power consumption that would otherwise occur if the coil were powered continuously. In some latching relay designs a brief relay coil current flowing in the reverse direction will return the switch to its original position. Other latching relay designs cause their switch to toggle between states when activated by a second current pulse of the same polarity, or even without regard to the polarity of the coil current.
While the use of relays in various electrical circuits is common, the function of the relay and relay components has traditionally been limited to the switching functions of the relay. Additionally, relays may be somewhat bulky, and in modern microelectronics may represent one of the larger or largest components of some circuits. Therefore, traditional relays are limited by their limited functionality in combination with their size requirements.